It's harvest season for many gardeners across the United States. As we bring in our bounty of fruits and vegetables, it's the perfect time to highlight the important role sugar plays in food preservation.
Sugar is used in the canning and freezing of fruits to improve flavor and texture, and to preserve natural color and shape.
Through osmosis, sugar replaces some of the water in the fruit. This natural process preserves the fruit's inherent color, texture and shape by preventing the fruit's remaining water from leaving its cellular structures. As a result, the fruit's texture is protected against weakening during freezing and canning.
In addition, sugar, upon entering the cells, helps minimize oxidation, and prevents the fruit's firm texture from becoming mushy.
Sugar also increases the shelf life of products. For example, a fruit canned in a light syrup might not last as long as one canned with a heavy syrup. The same goes for those canned using alternative sweeteners.
Here are a few important tips to remember:
* Fruit to be canned should be placed in a syrup of greater sugar concentration than that of the fruit itself. Whole fruits with tough skins, such as Kieffer pears and kumquats, are impermeable to the sugar syrup unless precooked or unless the skins are pierced.
* Fruits to be frozen benefit from either a dry sugar pack or from freezing in a sugar syrup. For a dry sugar pack, the fruit is gently mixed with sugar, in a given proportion, so that each piece is coated. The choice of dry or syrup pack generally depends on the use to which the frozen fruit is to be put. Fruits packed in syrup are usually chosen for dessert, while fruits packed in dry sugar are preferred for cooking purposes.
* Some fruits such as blueberries, cranberries, raspberries, rhubarb may be frozen in a dry pack without sugar. However, these and all other fruits benefit greatly from the sugar pack regardless of the type used (dry or syrup).